This appears to not be the case, it is not required before calling IAQmeasure, as the example sketch shows.
No apparent value change or range change when added to example sketch.
I wonder if it's only required before restoring / setting a new initial baseline etc, which would come before IAQmeasure.
The library docs / comments clearly state that calling IAQInit is required after the device is started. https://github.com/adafruit/Adafruit_SGP30/blob/master/Adafruit_SGP30.cpp#L96-L101
This appears to not be the case, it is not required before calling IAQmeasure, as the example sketch shows. No apparent value change or range change when added to example sketch. I wonder if it's only required before restoring / setting a new initial baseline etc, which would come before IAQmeasure.